Contractible core or center



` (NoModeLj W. H. HOOPES 8v G. PAIST.

* GONTRAGTIBLE GOR 0R CENTER. Y N0. 278,551. Patented May 29.1883.

l ters; and We do hereby declare that the Tol;-

, UNITED STATES PATENT EEICE.

WILLIAM E.- EooPEs AND GEORGE PAIsT, oF BALTIMORE, MARYLAND.

" ICONTRCTIBLE CORE O R CENTER.

SPECIFICATION forming part of` Letters Patent No; 278,551, dated May 29, 1883. Application tiled December 19, 1882. (N o model.)

To all whom it 'may concern:

Be it known that we, 4WILLIAM H.`HooPEs and .GEORGE PAIST, of Baltimore, in the county of Baltimore, and in the State of Maryland, have invented certain new and useful Improvements in Gontractible Cores or Cenlowing is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in which- Figure l is a perspective view ot' our i-mproved core, having a portion of its .wall .broken away to show its interior construction.

Fig. 2 is a central longitudinal section of the` .in plastic material or brick; and to this end said `invention `consists in the construction of the contractible core, substantially as and for the purpose hereinafter specified.

1n the annexed drawings, A represents the shell or body of ,our core, constructed from a sheet ot' metal which is coiled into the form of a cylinder, and has its edges lapped. Withl in said cylinder is placed a plate of sheet metal, B, which corresponds therewith in length, and has a` breadthpreferably equal to one-half its circumferentialdimensions, and transversely conforms to the curvature of said cylinder. The plate B is provided at ditt'erent points along its length with pairs of slots b, which extend from near its edges diagonally toward its center, and engage each with a stud or pin, a that projects radially inward from the plate A, and is provided upon its inner end with ahead that prevents withdrawal from itsslot. The plate B is placed over the lapped edges of `the plate A, and onehalf of the studs a are secured within the 'latter near each edge, so that if said plate `B is moved longitudiuallyover or with reference 4to said studs themesult will 'be the expansion or contraction of the shell by the decreasing or increasingof the amount of lap of its said edges.

`contracted to be easily withdrawn.

to enable cyy rA handle, b', is attached to one end `of said plate for the purpose of enabling the same to be easily moved, and is preferably placed at the end, which must be drawn outward in order to contract the shell. In use the device is` expanded to the desired size and placed in position, and the brick laid in the usual manner, or the plastic material run or traveled around its exterior and permitted to set, after which the inner plateis moved lengthwise until the shell is sufficiently In constructing a sewerfor other opening having greater length than said core, the latter is but partially withdrawn each time, its Vinner end being allowed to project a short distance withinthe completed opening in order to secure a smooth interior and to avoid crookedness.

This device can be safely employed for the production of several diameters of' opening Within the same piece of Work, or for making a tapering opening, and in consequence of the large difference obtainable between its maxi. mum and itsminimum diameters will supply the place ot several cores of other construc- We are aware that cores constructed from sheet metal and adapted to he expanded and contracted oircumferentially have before been used, and therefore do not claim the same, broadly.

Having thus vfully set forth the nature and merits ot' our invention,what we claim as new Isu The hereinhet'ore-described core, consisting ofthe shell A, provided with studs aand having its edges overlapped, in combination with the plate B, having the converging slots b, substantially as and for the purposespecilied.

In testimony that we claim the foregoing we have hereunto set our. hands this 27th day o f November, 1882. s

WILLIAM ILIHOOPES. GEORGE PAIST.

Witnesses:

HEINRICH 0. TIEoK, FREDERICK C. DEEYER. y 

